The reasons this patient requires retrograde and antegrade pyelography is because there were three distinct abnormalities on IVP, which could have been responsible for the hematuria. IVP is a more sensitive for detection of small lesions of the ureter or renal pelvis. The IVP has a higher sensitivity and specificity than an abdominal plain film for the detection of stones and provides data about the degree of obstruction. The IVP can also visualize both the bladder and the upper urinary tracts. It was previously the diagnostic procedure of choice, but is no longer because of potential contrast reactions, lower sensitivity, and higher radiation exposure. In-patient in whom the ureter or renal pelvis is poorly visualized by IVP, retrograde and
